Existing audio distribution systems, such as stereo and surround sound, are based on an inflexible paradigm implementing a fixed number of channels from the point of production to the playback environment. Throughout the entire audio chain, there has traditionally been a one-to-one correspondence between the number of channels created and the number of channels physically transmitted or recorded. In some cases, the number of available channels is reduced through a process known as mix-down to accommodate playback configurations with fewer reproduction channels than the number provided in the transmission stream. Common examples of mix-down are mixing stereo to mono for reproduction over a single speaker and mixing multi-channel surround sound to stereo for two-speaker playback.
Audio distribution systems are also unsuited for 3D video applications because they are incapable of rendering sound accurately in three-dimensional space. These systems are limited by the number and position of speakers and by the fact that psychoacoustic principles are generally ignored. As a result, even the most elaborate sound systems create merely a rough simulation of an acoustic space, which does not approximate a true 3D or multi-dimensional presentation.